1. Field of the Invention
This invention relates to hyperbranched, functional poly(arylenes) and their preparation. References
P. J. Flory J. Amer. Chem. Soc., 74, 2718 (1952); "Principles of Polymer Chemistry", Cornell University Press, 1953, pp 361-370, discusses the theory of condensation polymerization of so-called AB.sub.n -type monomers wherein A and B functions condense together to form branched high polymers which attain high molecular weight without gelation. The theory predicts that polymerization of such monomers containing one A and nB functions leads to randomly branched polymers containing one unreacted A function and (n-1)x+1 unreacted B functions where x is the number of monomer units, said polymers being more polydisperse the higher the degree of polymerization. Examples of monomers of this type given by Flory are benzyl halides XCH.sub.2 --C.sub.6 H.sub.5, alkali metal salts of trihalophenols and D-glucose; the polymers are said to be soluble, non-crystalline and fusible when correctly prepared. Fully aromatic monomers of the AB.sub.n type, or polymers therefrom, are not disclosed.
Denkewalter et al. U.S. Pat. No. 4,289,872 disclose highly branched polyamides composed of at least four successive layers of lysine units, prepared by polycondensation of selected amino or carbonyl functions. Baker et al. U.S. Pat. No. 3,669,939 disclose highly branched condensation polymers prepared from polyhydroxymonocarboxylic acids (OH).sub.n R--CO.sub.2 H wherein R is a hydrocarbon radical of up to 22 carbon atoms optionally interrupted by a heteroatom, and n is 2-6. Monomers disclosed as particularly suitable are those of the formula (HOCH.sub.2).sub.2 --C(R.sup.3)CO.sub.2 H where R.sup.3 is alkyl or --CH.sub.2 OH. Aromatic monomers are not exemplified and apparently not contemplated.
Tomalia et al. U.S. Pat. Nos. 4,587,329, 4,568,737, 4,588,120, 4,507,466 and WO 84/02705 disclose dense star polymers containing core, core branches and terminal groups. These polymers are built up, layer after layer, from a core substance by selective condensation of functional groups; each successive layer becomes a core for the subsequent layer. Only aliphatic polyamides and polyethers are exemplified. The monomers are of the AB type and the polymers therefrom are said to be soluble and to have a molecular volume less than 80% of that of a conventional extended star polymer made from similar materials, molecular diameters being less than 2000 angstrom units.
M. Maciejewski J. Macromol. Sci.-Chem., A17 (4), 689 (1982) describes his concept of so-called shell topological compounds, preparation of which includes polymerization of a monomer of the XRY.sub.n type, where n is at least 2. Such polymerization results in a "cascade branched (uncrosslinked) molecule of spherical structure". Equations are provided which correlate, among other properties, molecular weight with sphere diameter. Although monomers employed in the present invention are of the XRY.sub.n type, the reference does not suggest polymerization of arylene monomers or the physical properties of the polyarylenes therefrom.
Several aryl-aryl coupling reactions are known. Miyaura et al. Synth. Comm, 11(7), 513 (1981) disclose the Pd-catalyzed coupling reaction of phenyl boronic acid with aryl halides, including aryl bromides, to give the corresponding biaryls: C.sub.6 H.sub.5 -B(OH).sub.2 +Br-C.sub.6 H.sub.4 -Z.fwdarw.C.sub.6 H.sub.4 -Z where Z is an inert substituent. Arylboronic acids are said to have major advantages over other organometallic compounds for coupling reactions of this type, and are said to be available in wide variety through use of functionalizing reactions of the parent arylboronic acid, such as nitration, oxidation and halogenation. This reference also discloses Pd or Ni-catalyzed coupling between aryl halides and aryl magnesium or zinc compounds. Preparation of dihaloarylboronic acids from trihaloarylenes via mono lithium intermediates is known or obvious; lithium dibromobenzene preparation is disclosed by Chen et al., J. Organomet. Chem., 251, 149 (1983).
Thompson et al. J. Org. Chem., 49(26), 5237 (1984) disclose the coupling of arylboronic acids with 5-bromonicotinates to yield 5-arylnicotinates.
Yamamoto et al., Bull. Chem. Soc. Japan, 51, 2091 (1978) disclose coupling of aryl halides such as p-chloro and p-bromobenzene and 1,3,5-trichlorobenzene in the presence of magnesium and a compound of a transition metal such as Ni or Pd to give polymers. These monomers are of the A.sub.2 or A.sub.3 type wherein only like functions are involved. This reference also discloses non-polymerizing coupling of aromatic Grignard reagents RMgX and aryl halides R'X, catalyzed by a transition metal, to give the product R-R'; R and R' can be aryl.
J. Lindley, Tetrahedron, 40(9), 1433 (1984) discloses coupling of aryl halides with aryl copper compounds to form diaryl compounds. I. P. Beletskaya, J. Organomet. Chem., 250, 551 (1983) discloses aryl-aryl coupling of aryl halides with aryltrialkyltin compounds.
None of the prior art discloses highly branched, functionalized, wholly aromatic poly(arylenes) prepared by the polymerization of ABn-type aromatic monomers, nor suggest the properties exhibited by such polymers.